Carbon electrode having protective covering, and process for producing same.



G. H. SGHROERS. CARBON ELECTRODE HAVING PROTEGTIVE COVERING, AND PROCESS FOR PRODUCING SAME.

APPLICATION FILED MAR. 14, 1913.

Patented Mar. 3, 1914.

UNITED STATES PATENT OFFICE.

CARI! HERMANN SCHEOEBS. OF DUISBURG-MEIPEBICH, GERMANY, ASSIGNOB TO GESELLSCHAFT FUR .TEEBVEBWEBTUNG M. B. 3., OF DUISBUBG-MEIDERICH,

GERMANY.

cannon nnnc'rnonn navme rno'rncrrvr covname. am) raocnss roa raonucme sane.

Specification of Letters Patent.

Patented Mar. 3, 1914.

To all whom it may concern Be it known that I, CARL HERMANN Sonnonns, a subject of the German Emperor, residin at No. 57 Neumiihlerstrasse, Duisburg-Mei erich, Germany, have invented certain new and useful Improvements in Carbon Electrodes'Having Protective Covering, and Processes for Producing Same, of which the following is a specification.

It is a well known fact that the carbon electrodes in electric furnaces are subject to considerable wasting by burning awa under the action of air or other oxi izing gases between the sockets or terminals of the furnace electrodes and the meltin hearth. If the electrode is left unprotecte thus burning awa of the portion exposed to the gases is liabe to render the electrode prematurely useless. It has already been proposed to remove this drawback by covering the surface of the electrode at the endangered places with wire fabric, fire proof materials and sheet metal casings for the p ose of increasing the life of the carbon bloc With the sameobject it has also been proposed toprotect the surface of the electrodes with an electro-deposited metal covering or to render the said surface unaffected by oxidizing; gases by covering the same with a coating of enamel or with a glaze or vitreous layer. It has also been proposed to convert the surface of the electrode into carbids or into graphite. All those proposed methods of rotecting the electrodes increase the cost of the electrodes considerabl because the electrodes have first to be manu actured in the usual manner and have then to be provided by a second proccles of the granular materials must be arranged as closely as possible to one another. The electrodes maybe forced out of a recelver through a nozzle or mouthpiece or the ma be rammed or pressed in a mold an in t e latter case they maybe subjectedto a subsequent pressing operation. The selection of the ranular material to be emplo ed will deEend upon whether the electro es are to ave a surface having good electrical conductivity over its entire extent or whether the electrodes are to have good conducting contact surfaces only for the head and'end sockets or terminals in which latter case the remaining parts of the surface of the electrodes may be protected by a bad electrical conductor against the action of the oxidizing ases. In the former case there may be use for instance metals such as iron, aluminium and copper. In the latter case there may be used for instance quartz, slate, magnesite, carborundum, blast furnace slag, aluminium oxid, and in fact an non-conducting materials provided that it Is unaffected by oxidizing gases especially at high temperature. It is immaterial for the purposes of this invention whether in the burning of the electrodes the granular materlal selected forms other compounds so long as these compounds retain the desired granular texture and possess the above mentloned ro rties.

In se ectmg the protective materials to be employed, the manner of working of the furnace and the products resulting therefrom must be taken into consideration 1n having a core a and a coating of resisting material.

What I claim is:--

1. A process for the production of protective coverings on carbon electrodes, more particularly for. use in electric furnaces,

which consists in providing the-surfaces of the electrodes before they. areburned, with a coating of' closely arranged-particles tive coverings on carbon electrodes, mpre.

particularly for use in electric furnaces, which consists in providing the surfaces of the electrodes before they are burned, with a coating of closely arranged particles of granular material unafl'ected by oxidizing gases especially at high temperatures, by

pressing, rolling, hammering, or otherwise embedding said granular material into the sl'irfaces of the electrodes.

3. As anew article of. manufacture, acarbon electrode having a protective layer of closely arranged particles of grannlarmatelial unaffected byoxidi'zing gases, embedded in its surface.

In testimony whereof I ailix my signature 11113113881108 of two Witnesses.

CARL HERMANN seuaoras. a. 5.1

Witnesses ALBERT Norm, HELEN NUFER. 

